Events on Friday, December 8th, 2023
- Preliminary Exam
- Detection and Characterization of Core Magnetic Fluctuations on DIII-D using Faraday-Effect Polarimetry
- Time: 1:30 pm - 3:30 pm
- Place: 2301 Sterling
- Speaker: Rachel Myers, Department of Physics Graduate Student
- Abstract: Internal, resistive MHD instabilities called tearing modes (TMs) significantly contribute to disruptions and confinement degradation in tokamaks. Measuring nonlinear TM coupling with high m/n near the magnetic axis can aid in understanding neoclassical TM seeding, growth, and decay. For this tracking, we use the Radial Interferometer-Polarimeter (RIP), which is sensitive to core-resonant magnetic fluctuations on DIII-D and has detected TMs well before they appear on edge magnetic sensing coils [Pandya, DPP invited talk 2021]. Here we employ RIP to analyze the impact on pre-existing TMs of multiple, emerging MHD modes that are never detected by the coils. In one example, RIP detects a higher-frequency mode coupled to both an n=2 mode and a lower-frequency mode that later diminishes. All three modes are resonant near the magnetic axis, and their interaction is only visible using RIP. In this talk we will also discuss tearing mode structure and its potential effects on RIP-measured tearing mode amplitudes.
Zoom link: - Q&A with ISS representative
- Time: 2:15 pm - 3:00 pm
- Place: 2241 Chamberlin
- Abstract: Sara Sheibani from ISS will be joining us. She will have a short presentation about ISS and then we’ll have plenty of time for questions. I encourage you to pose questions in advance, but feel free to just bring them along, too. Questions ahead can be added here: Hope to see you there! p.s. Come to ask questions. . .or come for the bagels and coffee! Either way, come join us!
- Host: Sharon Kahn and Arifa